Importance

Loading Importance Indicators...

Abstract

A PSK and phase modulation transmission system has a modulator and a demodulator. The modulator has a carrier frequency generator (21) coupled to a voltage controlled phase shifter (22). The modulation of the signal in the shifter (22) is controlled by modulation voltage generator (23). A transmitter (24) receives the output from the shifter (22) and transmits the modulated signal. The demodulator (30) includes a receiver section (31) for receiving the signal transmitted by the transmitter (24). The receiver (31) is coupled to a modified phase locked loop comprising a phase detector (32), a low pass filter (33), a sample and a hold circuit (34) and a voltage controlled oscillator (35). A lock control circuit (36) receives either the output from the receiver (31) or the output from the filter (33) to produce a lock in pulse from changes in the received signal or changes in the demodulated signal at the filter (33) for controlling the sample and hold circuit (34).

Loading the Abstract Image...

First Claim